Exercise: WebSockets

The backend chat service provides a WebSocket API at the URL wss:// After having connected, a client receives event messages when a user's state changes or a message is sent.

  • Use the JavaScript file store.js to store the fetched users and messages locally.
  • Implement subscribeUsers and subscribeMessages functions that connect to the corresponding WebSocket channels and update the local users and messages when event messages are received.
  • Invoke the two subscription functions after having fetched the existing users and messages.
  • Remove the polling mechanisms in the users and messages components, .